Luminous switching key- or push-button

ABSTRACT

A key- or push-button for controlling the switching on and off of at least one electrical circuit is provided with an elongated body extending through an aperture of a panel. The body and the panel are made essentially of transparent material covered with an opaque outer wall or coating, with the exception of the end of the body and of an annular root portion thereof registering with the aperture of the panel in one switching position, whereby the light produced by a bulb incorporated to said panel is selectively transmitted to the end of the button.

United States Patent [1 1 Bouvrande LUMINOUS SWITCHING KEY- OR PUSH-BUTTON [75] lnventor: Andre Maurice Bouvrande,

Boussey-Saint-Antoine, France [73] Assignee: Soclete de Telecommunications Electronique Aeronautlque et Maritime T. E. A. M.", Paris, France [22] Filed: Dec. 15, 1971 [21] Appl. No.: 208,298

[30] Foreign Application Priority Data Aug. 28, 1973 2,476,257 7/1949 Hoff 240/2 SP UX 2,672,551 3/1954 Hale et a1. 24018.16

3,163,739 12/1964 Hutt 240/2 SP X Primary Examiner-Fred L. Braun Attorney-Francis T. Carr and Theodore Ordman 5 7] ABSTRACT A keyor push-button for controlling the switching on and off of at least one electrical circuit is provided with an elongated body extending through an aperture of a panel. The body and the panel are made essentially of transparent material covered with an opaque outer wall or coating, with the exception of the end of the body and of an annular root portion thereof registering with the aperture of the panel in one switching position, whereby the light produced by a bulb incorporated to said panel is selectively transmitted to the end of the button.

10 Claims, 1 Drawing Figure PATENTEBmza ma AN. zorzwom .5 ZOCLmOL 1 LUMINOUS SWITCHING KEY- OR PUSH-BUTTON The present invention relates generally to keyor push-buttons which, by being pressed or released, enable the switching of at least one circuit, for instance at least one electric circuit, to be controlled manually, and concerns more particularly keyor push-buttons of this type comprising associated illuminating means, the lighted or extinguished state of which indicates the switching state of the circuit.

The main purpose of the invention is to provide such keyor push-buttons, which may be juxtaposed in a great number to form a complex switching keyboard while at the same time requiring little space and excluding any risk of confusion between the luminous signals.

It is not possible to use to this end the conventional solution consisting in juxtaposing to each key-button an associated luminous signal supplied by a circuit adapted to be switched by the said key-button, for such an arrangement would require excessive space and would certainly involve a risk of confusion between the luminous signals.

Another known solution, which also is to be discarded, consists in using key-buttons comprising a translucid body in which is incorporated a lamp or other light source supplied by an electric circuit adapted to be switched by the key-button, which thus itself constitutes the associated luminous signal. The drawback to this solution is that it not only leads to increased space for the key-button, but also to a mutual illumination of the juxtaposed key-buttons, thus certainly resulting in a risk of confusion between their respective positions.

The said drawbacks are eliminated by the present invention, which has for its object a luminous keyor push-button of the type comprising an elongated body which is movable through an aperture of a panel between two stable positions corresponding respectively to two distinct switching states, in one of which the said keyor push-button is illuminated by an associated light source, the said keyor push-button being characterized essentially in that it is illuminated only at its end, the body of the said button comprising an opaque tubular wall whose free end, preferably closed by an at least locally transparent or translucid wall, constitutes the only outlet for the light produced by the associated light source when the said button is in its illuminated position.

It is therefore possible to juxtapose buttons according to the invention in a very reduced space, without however any risk of mutual illumination and of uncertainty as to their respective positions, whatever may be the angle in which they are seen. r

In a known manner, the light source associated with each key-button may be incorporated in the latter and supplied from an electric circuit adapted to be closed by the said key-button in its illuminated position.

However and preferably, the light source is arranged at a distance from the key-button and concealed behind or in the panel through which it passes and remains lighted permanently, an optical switching device enabling the light to reach the interior of the said keybutton exclusively when the latter is in illuminated position.

Under such conditions, there is advantageously provided an opaque seal element carried by the panel and engaging the opaque tubular wall of the key-button body, whatever the position of the latter may be, so as to close the annular passageway between the said keybutton and the corresponding aperture of the said paneL,

According to a preferred form of embodiment of the optical switching device, the light proceeding from the light source is guided by a transparent layer incorporated with the said panel and opposite which is located a transparent peripheral portion of the body of the keybutton in illuminated position.

Such an arrangement offers the obvious advantage of enabling a great number of key-buttons to be selectively illuminated from one and the same light source, without there being any need of'using movable members other than the key-buttons themselves.

According to an essential' aspect of the invention, the opaque tubular wall of the key-button body contains a core of transparent material, the base of which constitutes the said transparent peripheral portion and the top of which falls short of the free end of the said wall.

Such an arrangement is advantageous in that, on the one hand, it imparts to the key-button a solid and, therefore, sturdy structure, and, on the other hand, it produces a directing effect of illumination which not only further reduces the risk of confusion during the inspection of the respective positions of the juxtaposed key-buttons, but moreover enables such an inspection to be carried out under the most unfavourable conditions, especially in the presence of obliqueor grazingincidence ambient light.

The said directing effect may be further increased by giving the top of the transparent core a convex shape at least along its periphery, so as to concentrate the light proceeding from the source over a quasi-punctual range.

Owing to its sturdy structure, the said transparent core may constitute the key-button body itself and be made solid with the pin ensuring its mechanical connection with the switching member actuated by the key-button.

In this case, the said pin advantageously extends into the transparent core through the medium of a pointed conical portion, the tip of which falls short of the top of the said core.

Such an arrangement is advantageous in that it favours a good guiding of the light through the transparent core and nullifies the apparent section of the pin seen from the outside.

The guiding of the light may be further improved by giving a concave shape to the end surface of the base of the transparent core and by covering it with a reflecting coating.

As a result of the above-mentioned advantages, the

- luminous key-button according to the invention is particularly adapted to be used in keyboards for the control of aeroplane, helicopter and other piloted craft equipments. Indeed, such complex keyboards are required to occupy a small space since a great number of them are juxtaposed in a reduced space, while at the same time remaining perfectly readable under the unfavourable light conditions occurring in the daytime at high altitudes.

Other characteristic features and advantages of the invention will appear more clearly from the following detaileddescription of a non-limitative example of embodiment illustrated by the appended drawing wherein:

The single FIGURE is a sectional view of a portion of a switching keyboard comprising two luminous keyor push-buttons according to the invention, one of which is released and the other pressed.

Each of the illustrated keyor push-buttons T comprises an opaque tubular wall 10, the external periphery of which is splined to ensure a better grip, and the free end of which is closed by an end-piece 11 fulfilling the function of a dust-cap. The end-piece 11, which is preferably transparent, may also be translucid and/or bear signs enabling the key-button or its function to be identified. The opaque tubular wall is passed onto a transparent core 12, the base 13 of which is provided with an end collar or shoulder restoring the continuity of the external surface of the key-button. The top 14 of the transparent core 12, which falls short of the free end of the opaque tubular wall 10, comprises a plane central portion surrounded by a convex connecting chamfer. The base of the transparent core 12 is solid with a pin 15 provided with a slot in which are engaged orthogonal pressure screws 16 ensuring the positive mechanical connection thereof with a sleeve 17 solid with the switching member (not shown) actuated by the key-button T. The pin 15 extends into the transparent core 12 through the medium of a conical portion 18 provided with flats enabling it to be set in the transparent core 12 and the tip of which falls considerably short of the top 14 of the latter. The opposite end face of the core 12 is concavely conical and covered with a reflecting coating 19.

Each of the key-buttons T thus constituted passes axially through an aperture 0 provided in a panel P forming the front support of the switching keyboard. The panel P has a composite structure and comprises a metal support plate 20 covered with a transparent plastics plate 21, the apparent face of which is itself covered with a translucid coating 22 on which is superposed an opaque external coating 23 in which are provided windows 24 forming readable patterns or signs. The transparent-material plate 21 is provided with at least one recess 25 containing a miniature lamp 26 supplied through the medium of a printed circuit 27 interposed between the transparent plate and its support 20.

Each of the key-buttons T is surrounded by a seal element J of reinforced elastomer material, set in a groove formed at the external opening of the aperture 0 of the panel P the seal element J connects the opaque coating 23 of the panel P with the opaque tubular wall 10 of the key-button T, whatever the axial position of the latter may be.

When a released key-button T is in the position (1) shown in the left portion of the drawing, the sleeve 17 is-located opposite the transparent-material plate 21, whereas the transparent portion 13 of the periphery of the key-button body is located at the level of the seal element J. Under such conditions, the luminous flux originating from the lamp 26 and guided by the transparent-material plate 21 can neither reach the transparent core 12 of the key-button T nor pass round the latter, owing to the presence of the seal element J. This means that the key-button T remains completely dark when in the OFF position (1).

When a key-button T is pressed and moved to the ON position (2) shown in the right portion of the drawing the apparent peripheral portion 13 of its transparent core .12 is located opposite the transparent-material plate 21 of the panel P. Under such conditions, the luminous flux originating from the lamp 26 and guided by the transparent-material plate 21 penetrates radially into the transparent core 12 of the key-button T. The said luminous flux is concentrated in the axial direction by being reflected by the conical extension 18 of the pin 15 and the reflecting coating 19 of the concave end surface of the core 12. The thus axially directed luminous flux is further concentrated as a result of the convex configuration of the top 14 of the transparent core 12 and escapes from the key-button T through its transparent end wall 11 in the form of an almost parallel axial beam. The intensity of and direction imparted to the light beam enable the switching on of the keybutton concerned to be readily verified without any risk of confusion with the adjacent key-buttons, whatever the ambient ligh conditions may be. Indeed, each key-button seen from its .top appears as an intensive and separate luminous point, the conical and pointed extension 16 of the pin 15 being invisible from the outside. In case the end wall 11 of the key-button T is not transparent but locally translucid, the intensity and direction imparted to .the luminous beam result in the bright or dark reference sign provided on the said wall appearing with a high contrast and therefore being clearly readable.

The key-buttons T shown in the drawing have a general shape of revolution. Although this shape is not compulsory, it will be noted that it enables the keybuttons to be used to drive in rotation a component such as a potentiometer associated with the switching members actuated by pressing or releasing the keybuttons.

Of course, the invention is by no means limited to the form of embodiment described and illustrated, which has been given by way of example only. In particular, it comprises all the means constituting technical equivalents to the means described as well as their combinations, should the latter be carried out according to the spirit of the invention.

What is claimed is:

1. A luminous push'button incorporated to a keyboard for actuating and signalling the state of an associated switch means having first and second states, said keyboard comprising a front panel provided with an aperture through which said push button extends and is reciprocally movable between first and second positions corresponding respectively to said first and second states of said switch means, said front panel including at least one outer, opaque layer and one inner, light-transmitting layer operatively illuminated by an associated light source concealed by said panel, said push-button comprising an elongated, transparent core having an outer end portion surrounded by an opaque tubular wall and a solid inner base portion having a pin longitudinally fitted therein and operatively connected to said switch means for actuation thereof, said base portion having an exposed, annular periphery positioned and dimensioned to register with said inner layer of said panel when said push-button is in a determined one of said first and-second positions and to be out of alignment with said inner layer when said push-button is in the other one of said positions, an opaque, annular seal element being operatively mounted on said panel around said aperture for slidably engaging said opaque tubular wall of said push-button in either position thereof.

2. A luminous push-button according to claim 1, wherein said opaque, tubular wall extends beyond the end surface of said outer end portion of said transparent core and is closed at its free end by an at least partially transparent end wall.

3. A luminous push-button according to claim 2, wherein said end surface of said outer end portion of said core is shaped, at least along its periphery, into a convex lens adapted to concentrate light onto said end wall.

4. A luminous push-button according to claim 1, wherein said pin is formed with a pointed conical end which is fitted in said base portion of said transparent core and the tip of which falls short of said outer end surface of said core.

5. A luminous push-button according to claim 4, wherein the end surface of said base portion of said core is concave and covered with a reflecting coating.

6. A luminous push-button according to claim 5, wherein said opaque, tubular wall extends beyond the end surface of said outer end portion of said transparent core and is closed at its free end by an at least partially transparent end wall.

7. A luminous push-button according to claim 6, wherein said end surface of said outer end portion of said core is shaped, at least along its periphery, into a convex lens adapted to concentrate light onto said end wall.

8. A luminous push-button according to claim I, wherein said panel comprises a transparent plate constituting said inner layer, the apparent outer face of which is provided with an opaque, reflecting coating constituting said outer layer.

9. A luminous push-button according to claim 8, wherein said transparent plate is formed with at least one. internal recess containing at least one permanently illuminated miniature lamp, constituting said light source.

10. A luminous push-button according to claim 9, wherein said panel comprises a printed circuit board underlying the inner face of said transparent plate and arranged for feeding electrical energy to said lamp. 

1. A luminous push-button incorporated to a keyboard for actuating and signalling the state of an associated switch means having first and second states, said keyboard comprising a front panel provided with an aperture through which said push button extends and is reciprocally movable between first and second positions corresponding respectively to said first and second states of said switch means, said front panel including at least one outer, opaque layer and one inner, light-transmitting layer operatively illuminated by an associated light source concealed by said panel, said push-button comprising an elongated, transparent core having an outer end portion surrounded by an opaque tubular wall and a solid inner base portion having a pin longitudinally fitted therein and operatively connected to said switch means for actuation thereof, said base portion having an exposed, annular periphery positioned and dimensioned to register with said inner layer of said panel when said push-button is in a determined one of said first and second positions and to be out of alignment with said inner layer when said push-button is in the other one of said positions, an opaque, annular seal element being operatively mounted on said panel around said aperture for slidably engaging said opaque tubular wall of said push-button in either position thereof.
 2. A luminous push-button according to claim 1, wherein said opaque, tubular wall extends beyond the end surface of said outer end portion of said transparent core and is closed at its free end by an at least partially transparent end wall.
 3. A luminous push-button according to claim 2, wherein said end surface of said outer end portion of said core is shaped, at least along its periphery, into a convex lens adapted to concentrate light onto said end wall.
 4. A luminous push-button according to claim 1, wherein said pin is formed with a pointed conical end which is fitted in said base portion of said transparent core and the tip of which falls short of said outer end surface of said core.
 5. A luminous push-button according to claim 4, wherein the end surface of said base portion of said core is concave and covered with a reflecting coating.
 6. A luminous push-button according to claim 5, wherein said opaque, tubular wall extends beyond the end surface of said outer end portion of said transparent core and is closed at its free end by an at least partially transparent end wall.
 7. A luminous push-button according to claim 6, wherein said end surface of said outer end portion of said core is shaped, at least along its periphery, into a convex lens adapted to concentrate light onto said end wall.
 8. A luminous push-button according to claim 1, whereIn said panel comprises a transparent plate constituting said inner layer, the apparent outer face of which is provided with an opaque, reflecting coating constituting said outer layer.
 9. A luminous push-button according to claim 8, wherein said transparent plate is formed with at least one internal recess containing at least one permanently illuminated miniature lamp constituting said light source.
 10. A luminous push-button according to claim 9, wherein said panel comprises a printed circuit board underlying the inner face of said transparent plate and arranged for feeding electrical energy to said lamp. 